ISO 16151 pdf download – Corrosion of metals and alloys 一 Accelerated cyclic tests with exposureto acidified salt spray, “dry” and “wet”conditions

ISO 16151 pdf download – Corrosion of metals and alloys 一 Accelerated cyclic tests with exposureto acidified salt spray, “dry” and “wet”conditions.
The exposure cabinet shall have a minimum capacity of 0,4 ma. For large-capacity cabinets, dunng periods of exposure to acidified salt spray, it shall be ensured that the necessary condition of homogeneity and distribution of spray are met. The upper parts of the cabinet shall be designed so that drops ci sprayed solution formed on its surface do not tall on the specimens being tested,
The size and shape of the cabinet shall be such that, dunng periods of exposure to salt mist spray, the rate of collection of solution in the cabinet is within the hmits specified in 7.2,
NOTE A schematic diagram of oiw possible design of exposure cabt.et and associated apparatus for accelerated cyclic tests with exposure to acidified salt spray, ‘dry’ and “wer conditions e shown m Nines B.
4.2 Humidity and temperature control
An appropriate system shall be used to maintain the cabinet and its contents at the specified temperature and humidity (see 7.1). The tern perate shall be measured at a position at least 100 mm from the walls of the cabinet
4.3 Spraying device
The device for spraying the acidified-salt solution shall comprise a supply of dean ai. of controlled pressure and humidity, a reservoir containing the solution to be sprayed, and one or more atomizers.
The compressed aW supplied to the atomizers shall be passed through a filter to remove all traces of oil or solid matter, and the atomizing pressure shall be at an overpressure of 70 kPa to 170 kPa. and preferably 98 kPa constant.
4.4 Air saturator
In order Ic prevent evaporation of water from the sprayed droplets, the air shall be humidified before entering the atomizer, by passage through a saturation tower containing hot water at a temperature several degrees Celsius higher than that of the cabinet.
During periods of exposure to the acidified-salt solution mist, the appropriate temperature depends on the pressure used and on the type of atomizer nozzle and shall be adjusted so that the rate of collection of spray in the cabinet, and the concentration of the collected spray, are kept within the specified limits (see 7.2). The level of water shall be maintained automatically to ensure adequate humidification.
The atomizers shall be made of inert material, for example glass or plastic materials. Baffles may be used to prevent direct i,,pact of spray on the test specimens and the use of a modem mist dispersion tower is preferatil. In obialning constant distribution of spray within the cabinet. The level of the acidified-salt solution in the supply tank shall be maintained automatically to ensure constant spray delivery throughout the test.
4.5 CollectIng devices
At least two suitable collecting devices shall be available, consisting of clean funnels with a collecting area of approxriately 80 cm2, made of glass or other chemicaly inert material, with the stems inserted into graduated cylinders or other similar containers. The ppose of the collecting devices Is to confirm that the collection rate is within specified linits (see 7.2) They shall be placed in the zone of the cabinet wtiere the test specimens are placed, at least one close to the spray inlet and one remote from the inlet and in such a way that only spray, and not the liquid falling from specimens or from parts of the cabinet, is collected.
For metals or alloy without organic coatrngs. and inorganic coating materials, the specimens shall be thoroughly cleaned with an appropriate organic solvent (hydrocarbon, with a boihng point between 60 C and 120 C) using a clean soft brush or an ultrasonic deaning device. The cleaning shall be carried out in a vessel ui of solvent. After cleaning, the specimens shall be rinsed with fresh solvent, then dried.
Unless otherwise specdled, specimens intentionally coaled with protective organic films should not be cleaned prIor to the lest. If cleaning is necessary, specimens shall be wiped with gauze Impregnated with ethanol. taking care not to damage the surface of the specimens
Care shai be taken that specimens are not contaminated after cleanmg by careless handling.